Rotary machines, such as large turbine-generator units driven by gas, steam, or wind, are commonly known machines used to produce electric power. Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and a rotor. The rotor typically includes a rotatable hub having one or more rotor blades attached thereto. The rotor blades capture kinetic energy of wind using known airfoil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
During installation and/or operation of a rotary machine, it is common for the machine to become imbalanced. For example, during installation of a wind turbine, faulty blade-zero marking or high pitch offsets may result in excessive vibration in the generator frame. In addition, manufacturing tolerances of the generator typically cause the generator to have a mass imbalance about its longitudinal axis, which causes vibrations within the wind turbine.
Rotary machines are designed to withstand a certain amount of vibrations; however, excessive vibrations can lead to the eventual wearing out, or even sudden failure, of machine parts. Further, replacement of vibration-worn parts of the rotary machine can require the unit to be taken off-line, increasing both time and expenses associated with the rotary machine. Thus, it would be advantageous to detect such vibrations before such damage occurs.
To facilitate preventing damage to the machine, the machine components are commonly monitored to detect performance issues, e.g. excessive vibrations that may cause component failure or damage. For example, certain conventional control technologies primarily focus on utilizing the phase lock loop (PLL), which is a control system that generates an output signal having a phase that is related to the phase of an input signal. For example, for a wind turbine, such a system detects a vibration signal of a rotor having a phase and relates it to a desired phase for the rotor. The system then adjusts the vibration signal to keep the phases matched. Such a control technology involves complex calculations and is sensitive to noise within the vibration signal that can lead to skewed results or incorrect detection of a particular frequency in the output signal.
Accordingly, an improved system and method that detects excessive vibrations and implements a corrective action so as to protect the rotary machine before damage occurs would be advantageous. More specifically, an improved system and method for protecting a rotary machine that addresses the aforementioned issued would be welcomed in the art.